The decision came after an "extensive" due diligence process, according to TWU Super chief executive Paul Sayer.
"With the assistance of Drew Vaughan of Dymond, Foulds & Vaughan, we determined that the BNP Paribas team understood and could satisfy our current and future needs in an ever-changing regulatory landscape," Mr Sayer said.
The due diligence process looked most closely at the areas of investment performance reporting, risk analytics and online solutions, he added.
"We look forward to working with the strong leadership team at BNP Paribas and to developing a close working relationship in order to provide first class services to our members," Mr Sayer said.
BNP Paribas Securities Services acting head Ian Perkins said his firm would help the super fund optimise its operation processes, including investment performance.
"We look forward to working with TWU Super ... [to minimise] risks through world-class analytics, [enhance] performance returns for their members and [provide] online solutions, all through a single platform," Mr Perkins said.
TWU Super is not the first NAB Asset Servicing client to jump ship to BNP Paribas in 2014.
Certitude Global Investment made the switch in April 2014, and Australian Unity moved over to BNP Paribas in October 2014.
